Multi-GPU Performance

Crysis

NVIDIA's own multi-GPU solution outperformed the GeForce GTX 280 when it launched, so it is not too surprising to see the Radeon HD 4870 in CrossFire mode doing the same. If AMD can put two of these things on a single card it will have a viable competitor for the GTX 280 as well as the GX2.

Call of Duty 4

AMD's architecture did very well under Call of Duty 4 in the single-card tests, with a single Radeon HD 4870 performing better than a GeForce GTX 260. The scaling from one to two cards is beyond perfect in CoD4, the reason being that we test on two different platforms (Intel X48 for CrossFire, NVIDIA 790i for all single-cards), the end result is a rare case where two of AMD's $300 cards actually outperform two of NVIDIA's $650 cards. By no means is it the norm, but it is a testament to the strength of AMD's RV770 GPU.

Enemy Territory: Quake Wars

CrossFire continues to scale poorly in Quake Wars, while NVIDIA's GeForce GTX 280 SLI completely dominates the charts here. The 4870 CF performance isn't terrible, it's actually in line with where it should be (2 x $300 cards are about as fast as 1 x $650 card).

Assassin's Creed

Even at 2560 x 1600 the high end configurations are bumping into a frame rate limiter, any of the very high end setups are capable of running Assassin's Creed very well.

Oblivion

The GeForce 9800 GTX+ does very well in Oblivion and a pair of them actually give the 4870 CF a run for its money, especially given that the GTX+ is a bit cheaper. While it's not the trend, it does illustrate that GPU performance can really vary from one application to the next. The Radeon HD 4870 is still faster, overall, just not in this case where it performs equally to a GTX+.

The Witcher

We've said it over and over again: while CrossFire doesn't scale as consistently as SLI, when it does, it has the potential to outscale SLI, and The Witcher is the perfect example of that. While the GeForce GTX 280 sees performance go up 55% from one to two cards, the Radeon HD 4870 sees a full 100% increase in performance.

It is worth noting that we are able to see these performance gains due to a late driver drop by AMD that enables CrossFire support in The Witcher. We do hope that AMD looks at enabling CrossFire in games other than those we test, but we do appreciate the quick turnaround in enabling support - at least once it was brought to their attention.